Spatial and Material Optimization for Novel Sustainable and Radio-Frequency-Friendly Micro-Homes
Round 1
Reviewer 1 Report
The manuscript addresses the issues of designing a sustainable, spatially optimized, and RF-friendly novel building from the view of spatial and material optimization. It is a very interesting topic and a novel angle of view. However, I cannot suggest accepting it immediately due to the following reasons
- 1. The writing of the whole paper needs to be improved as it is difficult to read. Some typos and voice problems (active/negative) require to be corrected, please see the notes in the manuscript.
- 2. A big concern with the manuscript is it does not clearly state the limitations of the proposed method (especially in the conclusion) and how it differsfrom the existing literature.
- Why the author uses UWB as the antenna in the RF propagation assessment (see Subsection 4.2)? The author mentioned WiFi in previous sections. It should be noted that UWB and WiFi are different in terms of signal property-UWB has much stronger penetration capability. Is it appropriate to use UWB in the assessment?
- 4. The numbers of the figures in the manuscript are confusing. Please make them in the correct order and uniform (i.e, Fig. X or Figure X).
- 5. In Section 4.1, the author states “most of the office environment are filled with metallic furniture whichhelps in increasing the level of reflections”. Is that true? Any example? Please justify.
More details including improvement of the figure resolution, notations of the parameters in the equations, some abbreviations, etc. can be found in the notes in the manu
Comments for author File: 
Comments.pdf
Author Response
Answers to Reviewer #1
We thank the reviewer for the very useful comments and suggestions that helped to improve the quality and clarity of the manuscript. We have highlighted in red the changes to the manuscript.
Comments
The manuscript addresses the issues of designing a sustainable, spatially optimized, and RF-friendly novel building from the view of spatial and material optimization. It is a very interesting topic and a novel angle of view. However, I cannot suggest accepting it immediately due to the following reasons
Comment #1:
The writing of the whole paper needs to be improved as it is difficult to read. Some typos and voice problems (active/negative) require to be corrected, please see the notes in the manuscript.
Answer:
We have carefully reviewed the manuscript for typos and language errors.
Comment #2:
A big concern with the manuscript is it does not clearly state the limitations of the proposed method (especially in the conclusion) and how it differs from the existing literature.
Answer:
Thanks for the comment. As a matter of fact, the main novelty of the paper is that is the first attempt to attempt to make a joint design of a novel building that is sustainable, spatially optimized, but also RF-friendly. We believe that it is becoming more and more important to consider the need/requirement of connectivity right in the initial phase of the design, together with the other user/inhabitant requirements. However, so far no works have properly addressed this issue.
Our paper presents a first effort in this direction. We have done a characterization of the dielectric properties of the novel building material and estimated the channel impulse response of an indoor environment made of such a building material through simulations. The simulations allowed us to have indications on how to improve its RF behavior. Of course, a more accurate analysis will require extensive experimental assessment in a real indoor environment. As a perspective, we plan to build a prototype house with the proposed "drugged" material to experimentally assess the performance of the RF sensing monitoring systems.
Moreover, the proposed solution has some other limitations: one has been mentioned in the conclusions (for example, the fact that the achieved drugged material is characterized by a strong change in the color), the other one is related to the workability of the drugged material, which has not been mentioned. Therefore, we have changed the conclusions as follows:
“In this preliminary phase of optimization, we have assessed the indoor RF propagation of the original material and the drugged material through simulations, which provide us already with useful indications. Of course, a more accurate optimization can be done by using an experimental assessment. As a perspective, we plan to build a prototype house with the proposed "drugged" material to experimentally assess the performance of the RF sensing monitoring systems.
Moreover, it must be outlined that the achieved materials have two main drawbacks: i) they are characterized by a strong change in color; ii) they lose in the workability as the introduction of the proposed material has an impact on the compactness of the miscellaneous during the manufacturing process of the brick. The change of the color calls for a further step of architectural spatial optimization. The final solution foresees a piece of furniture, which could be a technological totem positioned within the spaces, visible and spatially defined made of the designed material. The further optimization considering the workability might lead to different choices for the drugging material and this will be subject of future research activity.”
Also the abstract has been changed to make it more effective.
Comment #3
Why the author uses UWB as the antenna in the RF propagation assessment (see Subsection 4.2)? The author mentioned WiFi in previous sections. It should be noted that UWB and WiFi are different in terms of signal property-UWB has much stronger penetration capability. Is it appropriate to use UWB in the assessment?
Answer:
UWB and WiFi are definitely different from the signal property point of view. However, the interaction of the EM wave with the building material depends mainly by the frequency of the EM. The dielectric properties, from which such a behavior depends, are different for different frequencies of the EM wave. Practically, lower frequencies have better penetration than higher frequencies. The ability to penetrate walls and obstacles of UWB comes from the lower frequency components of the signal. However, we have used an UWB signal to make the characterization of the material from the dielectric point of view in order to have a characterization for a wide range of frequencies (large as the bandwidth of the signal). Then, we have estimated the dielectric properties of the material for the carrier frequency of the WiFi standard (more precisely at 2.4GHz).
However, this was not clearly explained. Therefore, we have modified the manuscript to better explain this point as follows:
To make the characterization of the dielectric properties of the material over a large range of frequencies, we have used an UWB antenna. From the measured scattering parameters over the range of frequencies shown in Fig. 7 and 8, it is possible to estimate the dielectric parameters at different carrier frequencies. We have used the Nicholson-Ross-Weir method to estimate the relative permittivity at 2.4GHz.
Comment #4
Why have you used samples of material with different widths?
Answer:
About the dimension of the sample material. For a good dielectric characterization using the measured scattering parameter and the NRW method, the sample should be wide and thin. We have chosen samples of different material with the same width and height. About the thickness of the sample, as soon as it is much shorter than the width and height, the estimation method can be considered valid. Therefore, for the cardboard and the metallic plane, we have used very thin samples. For the novel material, as it is difficult to cut thin slices of such a material, we have used two “bricks”, to have a large “front-plane” and a shorter thickness.
Comment #5
Why not to use a 3D simulator?
Answer:
A 3D ray tracing simulator of the RF propagation would provide a more accurate assessment of the RF behaviour of the building material. However, for the purpose of this paper, which is not the absolute and accurate characterization of the RF propagation inside the building, but the comparison of the propagation behavior when different building materials are used, the use of a 3D simulator is not expected to add much added value to the conclusions. On the other hand, its implementation would be much more complex.
Comment #6
The numbers of the figures in the manuscript are confusing. Please make them in the correct order and uniform (i.e, Fig. X or Figure X).
Answer:
We have ordered the Figures and made uniform notation (Figure rather than Fig.).
Comment #7
In Section 4.1, the author states “most of the office environment are filled with metallic furniture whichhelps in increasing the level of reflections”. Is that true? Any example? Please justify.
Answer:
Typical “low cost” office environments/open spaces used to have furniture made of metallic material (chest of drawers, locker, dividing panels). Probably this is no longer true as more modern furniture use different and novel type of materials. We have changed the sentence as follows: many \textit{old-style} office environments are filled with metallic furniture (chest of drawers, lockers, dividing panels) which used to help in increasing the level of reflections.
Comment #8
It is better to explain what is meant for eco-compatible
Answer
We have added the following sentence to the text:
“made of eco-compatible material which means of natural materials with a life cycle that is compatible with the environment as they are either recyclable or dispersible in the ambient without causing any damage.”
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Reviewer 2 Report
The idea is very good and its has been implemented. There are some figures are not discussed; some symbols are not defined; and the test set-up Figure 6 has to be improved for better clarity. Please see the detail in the attached file.
Comments for author File: Comments.pdf
Author Response
We thank the reviewer for the very useful comments and suggestions that helped to improve the quality and clarity of the manuscript. We have highlighted in red the changes to the manuscript.
Reviewer #2
The idea is very good and its has been implemented. There are some figures are not discussed; some symbols are not defined; and the test set-up Figure 6 has to be improved for better clarity. Please see the detail in the attached file.
Thanks for the useful suggestions. We have applied the proposed changes indicated in the text.
Reviewer 3 Report
It is my great pleasure to review this high-quality manuscript. From my side, this manuscript can be accepted after very minor revision. The following comments is that:
1. The English writing should be improved from your side.
2. The abstract section should be improved and strengthened from your side.
Author Response
We thank the reviewer for the very useful comments and suggestions that helped to improve the quality and clarity of the manuscript. We have highlighted in red the changes to the manuscript.
Reviewer #3
It is my great pleasure to review this high-quality manuscript. From my side, this manuscript can be accepted after very minor revision. The following comments is that:
Comment #1:
The English writing should be improved from your side.
Answer: we have improved the English.
Comment #2
The abstract section should be improved and strengthened from your side.
Answer:
Thanks to the reviewer for the useful suggestions. We have changed the abstract as follows:
“The paper addresses the issue of designing a novel building that is sustainable, spatially optimized and also RF-friendly. The latter term is used to indicate that the building materials guarantee good radio signal penetration (at the range of frequencies of interest for commonly used wireless standards) and good reflection behavior indoor, thus enabling the use of innovative RF-based non-invasive human monitoring systems that take advantage of a RF scattering rich environment. The need of connectivity is becoming more and more a key inhabitant requirement. Nevertheless, so far there are no examples of architectural designs that takes into account the need for connectivity at the beginning of the design stage. As a consequence, once the house and the building material have been already designed, providing high quality wireless connectivity services might become challenging. Therefore, the paper presents a research activity that has conducted to the design of a novel ”house-concept” for vulnerable social groups which is made of a novel sustainable building material. Such a novel building material has been experimentally characterized in terms of dielectric properties. Simulation results have showed that such a material is not RF-friendly and solutions have been proposed to improve its RF propagation behavior to enable the use of a novel RF-sensing monitoring system.”
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Round 2
Reviewer 1 Report
Dear all, thanks for solving all the problems and questions I concerned. I think there is no more technical problem in the manuscript. However, I still strongly suggest the author to carefully check the English writing (typo/format/gramma mistakes) in the manuscript, by a native English speaker if possible, before it can be ready for publication. For example, “how many time is spent on the bed” in Page 4, a “respectively” is missing at the end of sentence “… the permittivity and the tangent loss of the miscellaneous” in Page 11, the blank is missing in the last paragraph in conclusion part in Page 12, etc. Moreover, one more suggestion is that the author mentioned “Nicholson-Ross-Weir Method” in Subsection 4.1, maybe it is better to briefly describe this method or add a citation after the term.
Author Response
We have carefully revised the English of the paper.
Moreover, beside the references on the NRW method, which are inserted, we have inserted a short sentence to describe it, which is outlined in red.
Reviewer 2 Report
I happy to accept the paper for publication
Author Response
We thank the reviewer.
